Can ends, or so-called end closures, such as used for food and beverage cans, are typically formed in blanking and forming presses, such as mechanical dual action slide presses. However, press speeds are often limited by the ability to quickly remove the resultant blanked and formed ends, i.e., to make sure there is no interference by a formed end with the entry of sheet stock into the press tooling during the next press cycle.
Known prior art methods for discharging blanked and formed ends from a press include operating the press at an angle, such as at 45 degrees to the horizontal, to allow gravity discharge of formed ends. However, because such presses had to pull and return the die set on an angle, overall operational speeds of such presses were substantially reduced. Further, that method does not assure that the ends will be discharged simultaneously, or that they will remain in proper alignment and orientation relative to any associated conveyor belt, for example, as may be used to deliver such ends to following operations or to packaging equipment.
An additional known method of discharging formed ends includes using an air-blast to blow the ends from the press tooling onto associated conveyors. However, because of constraints on physically housing a conveyor next to an operating press, the conveyors are typically as much as two to three feet away. Thus, by the time a series of air-blasted end closure leaves the tooling and reaches the associated conveyor over such a distance, they drop onto it at staggered times, as some are under friction while others are slightly airborne. When so deposited on the conveyors, such air-discharged ends can be too close together, too far apart, or even stacked one upon another. This haphazard alignment renders them generally unusable for further operations, as such staggered or stacked alignment can cause jammed machinery during successive operations.
The present invention overcomes the prior art discharge methods and machinery, including the uneven spacing problems attendant therewith, by providing an overhead belt discharge apparatus mounted closely adjacent the press tooling. Such an overhead belt discharge apparatus is able to quickly collect and discharge blanked and formed end closures along guide tracks formed in a discharge plate to a discharge opening and to the awaiting cross conveyors or other discharge line equipment, all in a consistently-oriented and uniformly-spaced manner. Thus, the instant the blanked and formed shell end contacts the overhead discharge belt it is transported away to an associated cross conveyor, and then on to any following procedures, such as to can end edge curling machinery, for example. The speed of the overhead discharge belts can be adjusted, as needed, and can be pre-set to accommodate any given press speed. Further, due to the high operational speeds achievable with the present end discharge apparatus, the speed of the associated press can be substantially increased, thereby resulting in overall improved efficiency and operational speeds for the entire can end or so-called shell making operation.
With the present invention, the associated stamping press does not have to be mounted at an angle, since no gravity discharge is required for the formed ends. Instead, an upright press can be used which is easier to load and also easier to allow access to the die set and tooling for maintenance purposes. Further, an upright press reduces wear on the press tooling's leader pins, since there is no side load placed thereon such as occurs when operating a press on an angle like with the prior art discharge systems.
Although the present invention is most advantageously used with upright presses, the invention is not so limited and it can be employed with presses that are mounted at an angle. This can be especially advantageous when applying the present invention to the older-type presses that have the stamping station mounted at an angle.
The rotating discharge belts used with the present overhead discharge systems are sufficiently soft to allow each belt to readily grab and then draw the discharged end thereunder along the associated discharge tracks. Thus, there is no abrasion problem occurring to the coated side of the discharged end when it is in contact with the discharge belt. Instead, the so-called "public" i.e., uncoated side is the only part that slides on the discharge track, and then it is moved along a relatively non-abrasive surface. Further, since the present end discharge apparatus is located on the opposite side of the press from the infeeding sheet stock, it is easier to clear misfeeds and jams in the press tooling than when the sheet stock feed and end ejection equipment are on the same side of the press.
Thus, it is an object of the present invention to provide an overhead belt discharge apparatus for forming presses for container end closures which in a controlled manner rapidly and accurately discharges the ends to associated conveyor belts.
It is a further object of the present invention to provide end discharge apparatus which allows for vertical operation of the associated forming press and tooling.
It is yet a further object of the present invention to provide an overhead belt discharge system which utilizes air-blasts to quickly remove blanked and formed container ends from the die tooling to the awaiting rotating discharge belts, so as to provide rapid discharge of ends from the die tooling, thereby allowing increased operational speeds for the press and tooling.